THE CEPHALOPODA 



185 



arms 



FIG. 53. BELEMNITES. 



a, Restoration of the living Belemnite (modified from d'Orbignyf). 

 F, Funnel ; G, guard ; Pro., pro-ostracum. b, b' , Restoration o 

 phragmocone, in front view and section (after Crick). P, Protoconch ; 

 Phr., phragmocone; S, siphuncle. c t Atractites philippii Hjatt and 

 Smith, Carnic, California. Guard (G) partly broken open showing 

 phragmocone (Phr.}. (After Hyatt and Smith.) d, B.ekmnofsis 

 bessinns (d'Orbigny), Bathonian. e, Hibolites hastaius (Blainville), 

 Callovian (Oxford Clay). /, Hastites clavatus (Blainville), Char- 

 mouthian. g, Oxyteuthis acuius (Miller), Sinemurian. h, Coelo- 

 teuthis excavaius (Phillips), Sinemurian. d-h, Ventral views : dotted 

 lines indicate the alveolus, unbroken lines the grooves on the surface. 

 d'-h', Cross-sections, the dot marking the axis, d, After d'Orbigny ; 

 e-h, after Phillips. (All X |, except a). 



